What kind of fuse for additional SCC

[Robbert]

Hi all,
I have ordered two new solar charge controllers. The MPP Solar All In Ones will only be used for inverting.
In the current setup I have added two Class T fuses (one per inverter).
With the addion of the new SCC's I assume, I need to fuse the lines to the SCC's as well.
Do I need to do that with two additional Class T fuses?

I attached a drawing of the new setup that will come in a month or so.

 

[fafrd]

Hi all,
I have ordered two new solar charge controllers. The MPP Solar All In Ones will only be used for inverting.
In the current setup I have added two Class T fuses (one per inverter).
With the addion of the new SCC's I assume, I need to fuse the lines to the SCC's as well.
Do I need to do that with two additional Class T fuses?

I attached a drawing of the new setup that will come in a month or so. View attachment 152849

I use breakers (which also serve as on-off switches) on each SCC…

 

[rodrick]

Why did you buy a aio just for inverting and choose not to use the mppt’s just wondering?

 

[fafrd]

Why did you buy a aio just for inverting and choose not to use the mppt’s just wondering?

I’m guessing the AIOs have higher minimum string voltage requirement than his PV string supports.

The SCCs generally support lower string voltages than the AIOs…

 

[Robbert]

Why did you buy a aio just for inverting and choose not to use the mppt’s just wondering?

The reason why I ordered separate charge controllers is because one of the inverters sometimes gives an error and freezes totally. MPP Solar promised to provide me with new firmware, but i did not get it.

It only happens when there is a lot of sun and the loads are very low. The error did not occur since weeks now, but I don't trust it anymore. When I am away for a holliday, I can't have this. Apparently it has to do with the SBU setting in combination of high solar and low loads.

In addition I will add some panels to the system, so the problem only can get bigger, if it truly is due to high solar input in combination with low loads.

 

[fafrd]

The reason why I ordered separate charge controllers is because one of the inverters sometimes gives an error and freezes totally. MPP Solar promised to provide me with new firmware, but i did not get it.

It only happens when there is a lot of sun and the loads are very low. The error did not occur since weeks now, but I don't trust it anymore. When I am away for a holliday, I can't have this. Apparently it has to do with the SBU setting in combination of high solar and low loads.

In SBU once the battery is full and can no longer charge, if incoming solar power is more than thhat required to offset loads, excess solar power either needs to be exported or curtailed.

If your MPP AIO is set to prevent export and is unable to curtail incoming solar power, that probably causes a fault condition.

 

[Robbert]

In SBU once the battery is full and can no longer charge, if incoming solar power is more than thhat required to offset loads, excess solar power either needs to be exported or curtailed.

If your MPP AIO is set to prevent export and is unable to curtail incoming solar power, that probably causes a fault condition.

yep I think you are right. according to the attached thread, it indeed has something to do with 'breaking' the SCC. Apparently this could be fixed by new firmware, but am still waiting for it. I hope that new SCC's will fix this.

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